It is well known that a valve apparatus includes a sleeve which is a hollowed tubular shaped and a valve member which is disposed in the sleeve. Further, the valve member opens and closes a port of the sleeve. The valve apparatus is provided in a hydraulic circuit of an automatic transmission of a vehicle, and is applied to a hydraulic control valve supplying an operation oil to a friction engaging mechanism.
In this case, generally, a filter for filtering the operation oil is provided in the valve apparatus. The filter is formed by a belt-shaped member which is wound around a bottom surface of a ring-shaped groove of the sleeve as a ring shape such that a first end part of the belt-shaped member overlaps a second end part of the belt-shaped member. The operation oil is filtered by the filter, and then is introduced into the port opened at the bottom surface.
However, in an overlapped part between the first end part and the second end part, a sieve opening is blocked, and a filtration efficiency is magnificently deteriorated. According to JP-2005-36912A (US 2005/0011703 A1), a rotation preventing portion is provided to prevent the filter from rotating relative to the sleeve, such that a peripheral-direction position of the overlapped part does not match an opening position of the bottom of the ring-shaped groove. The rotation preventing portion includes a depression part and a protrusion part. The depression part is depressed from a side surface of the ring-shaped groove in an axial direction of the sleeve, and the protrusion part is protruded from the filter toward the depression part.
However, according to JP-2005-36912A, since the depression part is provided, a length of the outer wall of the sleeve in the axial direction becomes not even. Therefore, a seal performance between the sleeve and a valve body to which the sleeve is mounted to is deteriorated.
Further, according to JP-2005-36912A, since it is necessary to form the depression part by milling, a manufacturing cost of the sleeve is increased.